Techniques for migration paths

ABSTRACT

Exemplary embodiments described herein relate to a destination path for use with multiple different types of VMs, and techniques for using the destination path to convert, copy, or move data objects stored in one type of VM to another type of VM. The destination path represents a standardized (canonical) way to refer to VM objects from a proprietary VM. A destination location may be specified using the canonical destination path, and the location may be converted into a hypervisor-specific destination location. A source data object may be copied or moved to the destination location using a hypervisor-agnostic path.

RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 14/870,095, filed on Sep. 30, 2015 and entitled“Techniques for Migration Paths,” which is a continuation-in-part of,and claims priority to, U.S. patent application Ser. No. 14/841,828,filed on Jul. 31, 2015 and entitled “Techniques to Manage DataMigration,” which claims priority to U.S. Provisional Application No.62/161,802, filed on May 14, 2015 and entitled “Techniques to ManageData Migration,” and is also a continuation-in-part of, and claimspriority to, U.S. patent application Ser. No. 14/712,845, filed on May14, 2015 and entitled “Techniques for Data Migration.” The contents ofthe aforementioned applications are incorporated herein by reference.

BACKGROUND

A virtual machine (VM) is a software implementation of a machine, suchas a computer, that executes programs like a physical machine. A VMallows multiple operating systems to co-exist on a same hardwareplatform in strong isolation from each other, utilize differentinstruction set architectures, and facilitate high-availability anddisaster recovery operations.

In some situations, it may be desirable to change from one type of VMarchitecture to another and/or to move data hosted at one type ofvirtual machine into another type of virtual machine. Typically, thisrequires that the information in the current (source) VM be copied intothe new (destination) VM. Migrating data between VM architectures,however, may be problematic. For instance, different types of VMs mayuse different, possibly proprietary, conventions for locating objectsstored in the VM hypervisor's file system or namespace.

As a result, migration may be a complex process that must be overseen bya skilled administrator familiar with architecture-specific namingconventions and commands that must be executed on the source VM anddestination VM in order to effect the migration. Accordingly, migrationmay cause a disruption in services, lengthy migration times, or in somecases lead to data corruption.

SUMMARY

Exemplary embodiments described herein relate to a destination path foruse with multiple different types of VMs, and techniques for using thedestination path to convert, copy, or move data objects stored in onetype of VM to another type of VM. The destination path represents astandardized (canonical) way to refer to VM objects from a proprietaryVM. A destination location may be specified using the canonicaldestination path, and the location may be converted into ahypervisor-specific destination location. A source data object may becopied or moved to the destination location using a hypervisor-agnosticdata object. In one embodiment, an exemplary conversion procedureinvolves: specifying a destination VM name and a destination locationusing a canonical destination path, discovering the disks associatedwith the destination VM, using the canonical destination path to findthe location within the destination disks; and using ahypervisor-agnostic command, copying source disk objects or files intothe discovered destination disks through a hypervisor-agnostic dataobject.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts an exemplary cluster hosting virtual machines.

FIG. 1B depicts an exemplary environment suitable for use withembodiments described herein.

FIG. 2 depicts exemplary interactions between components of exemplaryembodiments.

FIG. 3 depicts exemplary virtual machine migration system suitable foruse with exemplary embodiments described herein.

FIG. 4 depicts an exemplary centralized system suitable for use withexemplary embodiments described herein.

FIG. 5 depicts an exemplary distributed system suitable for use withexemplary embodiments described herein.

FIG. 6A depicts an exemplary method for copying a source disk object toa destination location using an exemplary destination path.

FIG. 6B depicts exemplary computing logic suitable for carrying out themethod depicted in FIG. 6B.

FIG. 6C depicts an exemplary system context diagram illustrating theexemplary method of FIG. 6A in connection with a suitable storageenvironment.

FIG. 7 depicts an exemplary method for migrating a virtual machine fromone type of hypervisor to another.

FIG. 8 depicts an exemplary computing device suitable for use withexemplary embodiments.

FIG. 9 depicts an exemplary network environment suitable for use withexemplary embodiments.

DETAILED DESCRIPTION

According to exemplary embodiments, an execution environment platformknown as the virtual machine (VM) abstracts a hardware platform from theperspective of a guest OS running on the VM. The abstraction of thehardware platform is performed by a hypervisor, also known as a virtualmachine monitor, which runs as a piece of software on a host OS. Thehost OS typically runs on an actual hardware platform, though multipletiers of abstraction may be possible.

While the actions of the guest OS are performed using the actualhardware platform, access to this platform is mediated by thehypervisor. For instance, virtual network interfaces may be presented tothe guest OS that present the actual network interfaces of the basehardware platform through an intermediary software layer. The processesof the guest OS and its guest applications may execute their codedirectly on the processors of the base hardware platform, but under themanagement of the hypervisor.

Multiple vendors provide hypervisors for the execution of virtualmachines using abstraction technology unique to the vendor'simplementation. The vendors use technology selected according to theirown development process. However these are frequently different fromvendor to vendor. Consequently, the guest OS has tailored virtualhardware and drivers to support the vendor implementation. Thisvariation may lead to a core incompatibility between VM platforms. Forexample, different VM platforms may use different technologies forbridging to a network, where virtualized network interfaces arepresented to the guest OS.

Similarly, different VM platforms may use different formats forarranging the data stored in virtual disks onto actual storage hardware.As such, moving data objects stored in a disk managed by a source VMinto a disk managed by a destination VM can be complex and may require agreat deal of knowledge of both the source and destination VMs.

By way of non-limiting example, a HyperV hypervisor may represent a pathto a virtual disk in the following manner:

\\cifsServeAcifsShare\dirName\diskName.vhdx

Meanwhile, an ESX hypervisor may represent a path to a virtual disk inthe following manner:

[datastoreName] \vmName\vmName.vmdk

where a path to a server datastore is represented in ESX in thefollowing manner:

datastoreName=nfsServer://volumeJunctionPath/subpath

As can be seen from the above, different hypervisors use differentformats for representing disk paths. Moreover, the disk paths usedifferent constituent components representing different concepts. Forinstance, HyperV uses the concept of a disk share, and ESX uses theconcept of a data store. Thus, users might need extensive knowledge ofproprietary hypervisor-specific data path formats and concepts in orderto locate data objects on a volume. Even after the data objects arelocated, it may be very difficult to move them to a different type ofhypervisor using different data paths.

According to exemplary embodiments, a destination path is provided forrepresenting a location of a data object stored in a disk associatedwith a virtual machine. The destination path represents the location ina standardized, canonical, hypervisor-agnostic format (e.g., a formatthat is independent of any particular hypervisor-vendor-specific formator style).

According to further embodiments, a method is provided for converting,moving, or copying one or more data objects stored on a disk associatedwith a source VM to a disk associated with a destination VM. Whenspecifying the destination of the data object(s), the destinationlocation may be specified according to the canonical destination path. Asystem may automatically convert the destination path name(behind-the-scenes and outside the visibility of an end user) into adestination path name using the destination hypervisor's namespace.Converting the data object may be performed with the assistance of ahypervisor-agnostic data object.

In order to copy or move the data object(s), the system may receive theidentification of the destination VM and a destination locationspecified using the canonical destination path. Using the destination VMidentification, the system may discover the disks associated with thedestination VM. The system may further retrieve a destination-sidestorage mapping that allows the system to map the canonical destinationpath to destination-side storage locations overseen by the destinationhypervisor, and may use a hypervisor-agnostic command to copy the sourcedata object(s) to the destination-side storage locations.

Reference is now made to the drawings, wherein like reference numeralsare used to refer to like elements throughout. In the followingdescription, for purposes of explanation, numerous specific details areset forth in order to provide a thorough understanding thereof. However,the novel embodiments can be practiced without these specific details.In other instances, well known structures and devices are shown in blockdiagram form in order to facilitate a description thereof. The intentionis to cover all modifications, equivalents, and alternatives consistentwith the claimed subject matter.

As used herein, the identifiers “a” and “b” and “c” and similardesignators are intended to be variables representing any positiveinteger. Thus, for example, if an implementation sets a value for a=5,then a complete set of components 122-a may include components 122-1,122-2, 122-3, 122-4 and 122-5. The embodiments are not limited in thiscontext.

System Overview

FIGS. 1A and 1B depict suitable environments in which the exemplarydestination paths and storage mappings may be employed.

FIG. 1A depicts an example of a cluster 10 suitable for use withexemplary embodiments. A cluster 10 represents a collection of one ormore nodes 12 that perform services, such as data storage or processing,on behalf of one or more clients 14.

In some embodiments, the nodes 12 may be special-purpose controllers,such as fabric-attached storage (FAS) controllers, optimized to run astorage operating system 16 and manage one or more attached storagedevices 18. The nodes 12 provide network ports that clients 14 may useto access the storage 18. The storage 18 may include one or more drivebays for hard disk drives (HDDs), flash storage, a combination of HDDsand flash storage, and other non-transitory computer-readable storagemediums.

The storage operating system 16 may be an operating system configured toreceive requests to read and/or write data to one of the storage devices18 of the cluster 10, to perform load balancing and assign the data to aparticular storage device 18, and to perform read and/or writeoperations (among other capabilities). The storage operating system 16serves as the basis for virtualized shared storage infrastructures, andmay allow for nondisruptive operations, storage and operationalefficiency, and scalability over the lifetime of the system. One exampleof a storage operating system 16 is the Clustered Data ONTAP® operatingsystem of NetApp, Inc. of Sunnyvale, Calif.

The nodes 12 may be connected to each other using a network interconnect24. One example of a network interconnect 24 is a dedicated, redundant10-gigabit Ethernet interconnect. The interconnect 24 allows the nodes12 to act as a single entity in the form of the cluster 10.

A cluster 10 provides hardware resources, but clients 14 may access thestorage 18 in the cluster 10 through one or more storage virtualmachines (SVMs) 20. SVMs 20 may exist natively inside the cluster 10.The SVMs 20 define the storage available to the clients 14. SVMs 20define authentication, network access to the storage in the form oflogical interfaces (LIFs), and the storage itself in the form of storagearea network (SAN) logical unit numbers (LUNs) or network attachedstorage (NAS) volumes.

SVMs 20 store data for clients 14 in flexible storage volumes 22.Storage volumes 22 are logical containers that contain data used byapplications, which can include NAS data or SAN LUNs. The differentstorage volumes 22 may represent distinct physical drives (e.g.,different HDDs) and/or may represent portions of physical drives, suchthat more than one SVM 20 may share space on a single physical drive.

Clients 14 may be aware of SVMs 20, but they may be unaware of theunderlying cluster 10. The cluster 10 provides the physical resourcesthe SVMs 20 need in order to serve data. The clients 14 connect to anSVM 20, rather than to a physical storage array in the storage 18. Forexample, clients 14 require IP addresses, World Wide Port Names (WWPNs),NAS volumes, SMB (CIFS) shares, NFS exports, and LUNs. SVMs 20 definethese client-facing entities, and use the hardware of the cluster 10 todeliver the storage services. An SVM 20 is what users connect to whenthey access data.

Connectivity to SVMs 20 is provided through logical interfaces (LIFs). ALIF has an IP address or World Wide Port Name used by a client or hostto connect to an SVM 20. A LIF is hosted on a physical port. An SVM 20can have LIFs on any cluster node 12. Clients 14 can access dataregardless of the physical location of the data in the cluster 10. Thecluster 10 will use its interconnect 24 to route traffic to theappropriate location regardless of where the request arrives. LIFsvirtualize IP addresses or WWPNs, rather than permanently mapping IPaddresses and WWPNs to NIC and HBA ports. Each SVM 20 may use its owndedicated set of LIFs.

Thus, like compute virtual machines, SVMs 20 decouple services fromhardware. Unlike compute virtual machines, a single SVM 20 can use thenetwork ports and storage of many nodes 12, enabling scale-out. Onenode's 12 physical network ports and physical storage 18 also can beshared by many SVMs 20, enabling multi-tenancy.

A single cluster 10 can contain multiple SVMs 20 targeted for varioususe cases, including server and desktop virtualization, large NAScontent repositories, general-purpose file services, and enterpriseapplications. SVMs 20 can also be used to separate differentorganizational departments or tenants. The components of an SVM 20 arenot permanently tied to any specific piece of hardware in the cluster10. An SVM's volumes 22, LUNs, and logical interfaces can move todifferent physical locations inside the cluster 10 while maintaining thesame logical location to clients 14. While physical storage and networkaccess moves to a new location inside the cluster 10, clients 14 cancontinue accessing data in those volumes or LUNs, using those logicalinterfaces.

This capability allows a cluster 10 to continue serving data as physicalnodes 12 are added or removed from the cluster 10. It also enablesworkload rebalancing and native, nondisruptive migration of storageservices to different media types, such as flash, spinning media, orhybrid configurations. The separation of physical hardware from storageservices allows storage services to continue as all the physicalcomponents of a cluster are incrementally replaced. Each SVM 20 can haveits own authentication, its own storage, its own network segments, itsown users, and its own administrators. A single SVM 20 can use storage18 or network connectivity on any cluster node 12, enabling scale-out.New SVMs 20 can be provisioned on demand, without deploying additionalhardware.

One capability that may be provided by a storage OS 16 is storage volumesnapshotting. When a snapshot copy of a volume 22 is taken, a read-onlycopy of the data in the volume 22 at that point in time is created. Thatmeans that application administrators can restore LUNs using thesnapshot copy, and end users can restore their own files.

Snapshot copies are high-performance copies. When writes are made to aflexible volume 22 that has an older snapshot copy, the new writes aremade to free space on the underlying storage 18. This means that the oldcontents do not have to be moved to a new location. The old contentsstay in place, which means the system continues to perform quickly, evenif there are many Snapshot copies on the system. Volumes 22 can thus bemirrored, archived, or nondisruptively moved to other aggregates.

Therefore, snapshotting allows clients 14 to continue accessing data asthat data is moved to other cluster nodes. A cluster 10 may to continueserving data as physical nodes 12 are added or removed from it. It alsoenables workload rebalancing and nondisruptive migration of storageservices to different media types. No matter where a volume 22 goes, itkeeps its identity. That means that its snapshot copies, its replicationrelationships, its deduplication, and other characteristics of theflexible volume remain the same.

The storage operating system 16 may utilize hypervisor-agnostic orhypervisor-independent formatting, destination paths, and configurationoptions for storing data objects in the storage devices 18. For example,Clustered Data ONTAP® uses the NetApp WAFL® (Write Anywhere File Layout)system, which delivers storage and operational efficiency technologiessuch as fast, storage-efficient copies; thin provisioning; volume, LUN,and file cloning; deduplication; and compression. WAFL® accelerateswrite operations using nonvolitile memory inside the storage controller,in conjuction with optimized file layout on the underlying storagemedia. Clustered Data ONTAP® offers integration with hypervisors such asVMware ESX® and Microsoft® Hyper-V®. Most of the same features areavailable regardless of the protocol in use.

Although the data objects stored in each VM's storage volume 22 may beexposed to the client 14 according to hypervisor-specific formatting andpath settings, the underlying data may be represented according to thestorage operating system's hypervisor-agnostic configuration.

Management of the cluster 10 is often performed through a managementnetwork. Cluster management traffic can be placed on a separate physicalnetwork to provide increased security. Together, the nodes 12 in thecluster 10, their client-facing network ports (which can reside indifferent network segments), and their attached storage 18 form a singleresource pool.

FIG. 1B shows the configuration of the SVMs 20 in more detail. A client14 may be provided with access to one or more VMs 20 through a node 12,which may be a server. Typically, a guest operating system (distinctfrom the storage OS 18) runs in a VM 20 on top of an executionenvironment platform 26, which abstracts a hardware platform from theperspective of the guest OS. The abstraction of the hardware platform,and the providing of the virtual machine 20, is performed by ahypervisor 28, also known as a virtual machine monitor, which runs as apiece of software on a host OS. The host OS typically runs on an actualhardware platform, though multiple tiers of abstraction may be possible.While the actions of the guest OS are performed using the actualhardware platform, access to this platform is mediated by the hypervisor28.

For instance, virtual network interfaces may be presented to the guestOS that present the actual network interfaces of the base hardwareplatform through an intermediary software layer. The processes of theguest OS and its guest applications may execute their code directly onthe processors of the base hardware platform, but under the managementof the hypervisor 28.

Data used by the VMs 20 may be stored in the storage system 18. Thestorage system 18 may be on the same local hardware as the VMs 20, ormay be remote from the VMs 20. The hypervisor 28 may manage the storageand retrieval of data from the data storage system 18 on behalf of theVMs 20. Different types of VMs 20 may be associated with differenthypervisors 28. Each type of hypervisor 28 may store and retrieve datausing a hypervisor-specific style or format.

For example, multiple vendors provide hypervisors 28 for the executionof virtual machines 20 using abstraction technology unique to thevendor's implementation. The vendors use technology selected accordingto their own development process. However this technology is frequentlydifferent from vendor to vendor. Consequently, the guest OS has tailoredvirtual hardware and drivers to support the vendor implementation. Thisvariation may lead to a core incompatibility between VM platforms. Forexample, different VM platforms may use different technologies forbridging to a network, where virtualized network interfaces arepresented to the guest OS. Similarly, different VM platforms may usedifferent formats for arranging the data stored in virtual disks ontoactual storage hardware.

In some circumstances, an administrator may wish to migrate existing VMs20 running under the management of one type of hypervisor 28 tomanagement by a different type of hypervisor 28. However, given theproprietary nature of hypervisor technology, VM migration may be verycomplex. For example, migrating a guest OS from one VM platform toanother may require reconfiguration of the guest OS and modification offiles stored on the host OS that are referenced by the hypervisor 28.

As used herein, migration refers to moving a virtual machine 20 from asource to a destination. In a migration operation, the virtual hardwareentities associated with the virtual machine 20 (including thevirtualized CPU, network card, memory, peripherals such as a DVD player,etc.) are recreated at the destination hypervisor 28. Migration can be acomplicated operation, in which the sequence of operations can beimportant in order to provide reliable and accurate conversion of thedata.

Traditionally, in order to migrate from one hypervisor 28 to another, anadministrator may issue a complicated series of commands thatreconfigures and converts a source VM into a destination VM. This mayinvolve issuing commands to copy data from the source VM to thedestination VM, which takes a significant amount of time (hours todays). This is typically a manual process requiring a great deal ofknowledge of both the source VM platform and the destination VM platformand the associated commands that are used to reconfigure and converteach type of VM.

Because different hypervisors 28 format and store data according todifferent methodologies, it may be especially difficult to specify oridentify the destination of the data transfer. The transfer may involvemultiple steps requiring the location of the data to be specifiedaccording to different formats. A user desiring to migrate to adestination VM may be familiar with the style or formatting of thedestination VM, but may be unfamiliar with the source VM or theintermediate formats. Exemplary embodiments address this problem byleveraging the above-described hypervisor-agnostic formatting of thestorage OS 16 to copy or move the data automatically andbehind-the-scenes. The end user may specify the destination of the datausing the formatting style of the destination VM, without the need to befamiliar with source or intermediate formatting styles.

A general overview of an exemplary data migration is next described forcontext. FIG. 2 depicts exemplary interactions between the components ofthe exemplary environment as they perform a migration from one virtualmachine (referred to as a source virtual machine) to another virtualmachine (referred to as a destination virtual machine). The migrationmay involve copying the data associated with the source virtual machineto storage volumes managed by the destination virtual machine, andrecreating the configuration of the source virtual machine (such asnetwork interfaces and user configuration settings) on the destinationvirtual machine.

As shown in FIG. 2, a virtual machine migration system 30 may include aclient 14, a migration server 32, and one or more hypervisors 28 and/orstorage resources 18.

The client 14 may be a computing device through which a user or logic isable to execute commands (e.g., in the form of cmdlets 34, such asPowerShell cmdlets). The commands may be executed from an application orscript 36.

The client 12 may initiate the migration of a guest OS 38 from a sourceVM managed by a source hypervisor 28 to a destination VM managed by adestination hypervisor 28. Data associated with the source VM and/or thedestination VM may be stored in data storage 18 managed by a storagevirtual machine (SVM) 20, such as an SVM provided by a Data ONTAPCluster.

The migration may be carried out by issuing the commands to a migrationserver 32, which performs the migration. The migration recreates thevirtual hardware entities associated with the virtual machine at thedestination hypervisor. In performing the migration operation, only asource disk image is copied to the destination; the hardware setup isreconfigured to exist at the destination in the same configuration as atthe source.

The migration server exposes an interface 40, such as a RESTful API. Theinterface 40 allows the client 14 to execute interface commands (e.g.,methods or functions), which may have a one-to-one correspondence tocommands available through the cmdlets 34. In some embodiments, theclient 14 interacts directly with the interface 40 (e.g., by having auser issue commands to the interface 40 using the cmdlets 34 directly);however, as described in more detail below there may be advantages tointeracting with the interface 40 indirectly through scripts 36 thatcall the cmdlets 34.

The interface 40 abstracts away many of the operations required toperform the migration. This allows the commands sent to the interface 40to be relatively simple (e.g., a “convert” command that specifies only aVM name and a direction from a source VM type to a destination VM type).Commands issued to the interface 40 may be handled by a web server 42,such as an Apache Tomcat servlet.

The commands issued to the interface 40 may then be sent to a HypervisorShifting API 44, which includes functionality for determining whichhypervisor-specific commands need to be called in order to carry out theconvert operation, and then calling the hypervisor-specific commandsthrough proprietary APIs (e.g., APIs exposed by the ESX Server, Hyper-VServer, or a VMWare API such as VI Java or PowerCLl). Thehypervisor-specific commands may be executed by hypervisor-specificservices 46.

The guest OS 38 may be presented a virtual disk by the virtual machines20, where the virtual disk is an abstraction of the physical storageused by the virtual machines 20. A file system in a data storage 18 maystore a source VM virtual disk, where the source VM virtual disk is anarrangement of blocks corresponding to a virtual disk format used by thesource hypervisor. The file system may further store a destination VMvirtual disk, where the destination VM virtual disk is an arrangement ofblocks corresponding to a virtual disk format used by the destinationhypervisor. The source VM virtual disk and the destination VM virtualdisk may be built from almost entirely the same set of blocks, with thecommon blocks being those that correspond to the storage of data visibleto the guest OS 38, as described in more detail below in connection withFIG. 3.

Each of the source VM virtual disk and the destination VM virtual diskmay have one or more blocks dedicated to storage of data and metadataused by the source hypervisor and destination hypervisor, respectively,that are not accessible to the guest OS 38. For example, one block maybe exclusively used by the source hypervisor for storing data andmetadata used for managing its access to the common blocks.

Because of the above-noted overlap in storage blocks, transitioning fromthe source hypervisor to the destination hypervisor may involve simplycreating a new block, with data and metadata for managing the commonblocks, and constructing a destination VM virtual disk from those blocksused by source VM virtual disk that are not exclusive to the managementdata and metadata of source hypervisor.

Prior to migration, the data for the VMs may be stored in ahypervisor-agnostic data format (e.g., the Data ONTAP data format) in adata storage 18 embodied as an ONTAP storage cluster. Although ONTAPallows the underlying VM data to be exposed in different ways (e.g.,using different storage location formats) depending on the type of VM 20associated with the data, ONTAP maintains a common representation thatcan be used to quickly convert the data from one VM 20 to another (e.g.,in constant time, typically requiring minutes at most). Other types ofdata storage devices and formats may also be used in conjunction withexemplary embodiments, such as the NetApp E-Series and EMC array.

A migration application 48 may interact with the source hypervisor, thedestination hypervisor, the guest OS 206, and the data storage 18 tomigrate the guest OS 38 running on the source VM from the sourcehypervisor to the destination hypervisor. The migration application 48may also migrate individual data objects stored in the common diskblocks from management by a source VM to management by a destination VM.

The migration application 48 may generate one or more scripts that runin the guest OS 38 running on top of each of the source VM and thedestination VM to perform the migration. The migration application 48may use one or more scripts that run in the guest OS 38 on top of thesource VM to gather configuration information for use in generation ofone or more scripts that run in the guest OS 38 on top of destinationVM. The migration application 48 may also make use of a storage mapping50 to manage the migration of data stored in the data storage from thesource VM to the destination VM. The storage mapping 50 is described inmore detail below with respect to FIGS. 6A-7.

The migration application 48 may send commands to and monitor the sourcehypervisor and destination hypervisor. For instance, the migrationapplication 48 may script or use direct commands to initiate powercycles of the virtual machines 20 and use the power cycling of virtualmachines 20 to monitor the progress of scripts. By using scripts thatuse the built-in scripting of the guest OS 38, the migration application48 may avoid installing software agents within the guest OS forperforming the migration, thereby simplifying the migration process.

Virtual Machine Migration System

FIG. 3 is a block diagram depicting an exemplary virtual machinemigration system 100 for carrying out the above-described migration. Inone embodiment, the virtual machine migration system 100 may comprise acomputer-implemented system having a software migration application 48comprising one or more components. Although the virtual machinemigration system 100 shown in FIG. 3 has a limited number of elements ina certain topology, it may be appreciated that the virtual machinemigration system 100 may include more or less elements in alternatetopologies as desired for a given implementation.

The virtual machine migration system 100 may comprise the migrationapplication 48. The migration application 48 may be generally arrangedto migrate guest OS 150 from source VM 140 running on source hypervisor130 to destination VM 145 running on destination hypervisor 135, whereineach of migration application 110, source hypervisor 130, anddestination hypervisor 135 all run on top of host OS 120.

The file system 160 may be a file system that stores data according tothe format or style of the storage operating system 16. File system 160may store various files used in the operation of source VM 140 anddestination VM 145, and thereby the operation of guest OS 140. Filesystem 160 may store various files used by migration application 48.File system 160 may store various files used by the host OS 120. Filesystem 160 may be provided by host OS 120 or may be a third-party filesystem working in conjunction by host OS 120. File system 160 may be alocal file system, a network-accessible file system, a distributed filesystem, or use any other file system techniques for the storage of,maintenance of, and access to files.

File system 160 may store source VM configuration file 180 used bysource hypervisor 130 for the determination of various configurations ofsource VM 140. File system 160 may store destination VM configurationfile 185 used by destination hypervisor 130 for the determination ofvarious configurations of source VM 140. Source VM configuration file180 may be composed of one or more source VM configuration file blocks195. Destination VM configuration file 185 may be composed of one ormore destination VM configuration file blocks 197. The configuration ofa virtual machine may comprise, among other elements, specifying theconfiguration of the hardware platform to be virtualized, such as numberand type of CPU, memory size, disk size, etc.

Guest OS 150 may be presented a virtual disk by the virtual machines,the virtual disk an abstraction of the physical storage used by thevirtual machines. File system 160 may store source VM virtual disk 170,where source VM virtual disk 170 is an arrangement of blockscorresponding to a virtual disk format used by the source hypervisor130. File system 160 may store destination VM virtual disk 175, wheredestination VM virtual disk 175 is an arrangement of blockscorresponding to a virtual disk format used by the destinationhypervisor 135. Virtual disk blocks 190 is the joint collection ofblocks used by both source VM virtual disk 170 and destination VMvirtual disk 175. Source VM virtual disk 170 and destination VM virtualdisk 175 may be able to be built from almost entirely the same set ofblocks, with the common blocks being those that correspond to thestorage of data visible to the guest OS 150. Each of the source VMvirtual disk 170 and destination VM virtual disk 175 may have one ormore blocks dedicated to storage of data and metadata used by the sourcehypervisor 130 and destination hypervisor 135, respectively, that is notaccessible to the guest OS 150. For example, block 191 may beexclusively used by source hypervisor 130 for storing data and metadataused for managing its access to the common blocks of virtual disk blocks190. Similarly, block 192 may be exclusively used by destinationhypervisor 135 for storing data and metadata used for managing itsaccess to the common blocks of virtual disk blocks 190. It will beappreciated that multiple blocks may be used by either or both of sourcehypervisor 130 and destination hypervisor 135 for the storage of thisdata and metadata. Because of this overlap in storage blockstransitioning from source hypervisor 130 to destination hypervisor 135may involve simply creating block 192, with its data and metadata formanaging the common blocks, and constructing destination VM virtual disk175 from those blocks used by source VM virtual disk 170 that are notexclusive to the management data and metadata of source hypervisor 130.

A data migration component or “agent” 155 may be installed in the guestOS 150 or may be a separate component in association with the guest OS150 and also may be in communication with a host hypervisor 130 or 135.Alternatively or in addition, the data migration component 155 may be aseparate entity run on a client device outside of the guest OS 150.

The data migration component 155 is controlled by a processor device andexecutes data migration tasks as described herein. The data migrationcomponent 155 may interact with the source hypervisor 130, thedestination hypervisor 135, the guest OS 150, and the file system 160 tomigrate data after detecting a change from the source hypervisor 130 tothe destination hypervisor 135 or visa versa. In one embodiment, thedata migration component 155 bypasses or eliminates the need for themigration application 110. When possible, the data migration component155 is automatically pushed and installed into the guest OS 150 when theguest OS 150 credentials are known, otherwise the installation isperformed by a user knowing the guest OS 150 credentials. Also, thein-guest utilities/tools may function as, and/or assist with, the datamigration component 155 to eliminate and/or reduce the need forcustomized software.

The migration application 110 may interact with the source hypervisor130, the destination hypervisor 135, the guest OS 150, and the filesystem 160 to migrate the guest OS 150 from the source hypervisor 130 tothe destination hypervisor 135. The migration application 110 maygenerate one or more scripts that run in the guest OS 150 running on topof each of the source VM 140 and the destination VM 145 to perform themigration. The migration application 110 may use one or more scriptsthat run in the guest OS 150 on top of the source VM 140 to gatherconfiguration information for use in generation of one or more scriptsthat run in the guest OS 150 on top of destination VM 145. The migrationapplication 110 may send commands to and monitor the source hypervisor130 and destination hypervisor 135. For instance, the migrationapplication 110 may script or use direct commands to initiate powercycles of the virtual machines and use the power cycling of virtualmachines to monitor the progress of scripts. By using scripts that usethe built-in scripting of the guest OS 150 the migration application 110may avoid installing software agents within the guest OS 150 forperforming the migration, thereby simplifying the migration process.

The above-described migration process may be carried out in acentralized environment (e.g., an environment in which the migrationapplication 48, source hypervisor 130, destination hypervisor 135, andfile system 160 are all hosted in the same device), or a distributedenvironment (in which some or all of these components are provided ondifferent devices). FIG. 4 depicts an exemplary centralized system 400,while FIG. 5 depicts an exemplary distributed system 500.

Centralized Embodiments

FIG. 4 illustrates a block diagram of a centralized system 400 that mayimplement some or all of the structure and/or operations for the virtualmachine migration system 100 in a single computing entity, such asentirely within a single device 420.

The device 420 may comprise any electronic device capable of receiving,processing, and sending information for the system 100. Examples of anelectronic device may include without limitation an ultra-mobile device,a mobile device, a personal digital assistant (PDA), a mobile computingdevice, a smart phone, a telephone, a digital telephone, a cellulartelephone, eBook readers, a handset, a one-way pager, a two-way pager, amessaging device, a computer, a personal computer (PC), a desktopcomputer, a laptop computer, a notebook computer, a netbook computer, ahandheld computer, a tablet computer, a server, a server array or serverfarm, a web server, a network server, an Internet server, a workstation, a mini-computer, a main frame computer, a supercomputer, anetwork appliance, a web appliance, a distributed computing system,multiprocessor systems, processor-based systems, consumer electronics,programmable consumer electronics, game devices, television, digitaltelevision, set top box, wireless access point, base station, subscriberstation, mobile subscriber center, radio network controller, router,hub, gateway, bridge, switch, machine, or combination thereof. Theembodiments are not limited in this context.

The device 420 may execute processing operations or logic for the system100 using a processing component 430. The processing component 430 maycomprise various hardware elements, software elements, or a combinationof both. Examples of hardware elements may include devices, logicdevices, components, processors, microprocessors, circuits, processorcircuits, circuit elements (e.g., transistors, resistors, capacitors,inductors, and so forth), integrated circuits, application specificintegrated circuits (ASIC), programmable logic devices (PLD), digitalsignal processors (DSP), field programmable gate array (FPGA), memoryunits, logic gates, registers, semiconductor device, chips, microchips,chip sets, and so forth. Examples of software elements may includesoftware components, programs, applications, computer programs,application programs, system programs, software development programs,machine programs, operating system software, middleware, firmware,software modules, routines, subroutines, functions, methods, procedures,software interfaces, application program interfaces (API), instructionsets, computing code, computer code, code segments, computer codesegments, words, values, symbols, or any combination thereof.Determining whether an embodiment is implemented using hardware elementsand/or software elements may vary in accordance with any number offactors, such as desired computational rate, power levels, heattolerances, processing cycle budget, input data rates, output datarates, memory resources, data bus speeds and other design or performanceconstraints, as desired for a given implementation.

The device 420 may execute communications operations or logic for thesystem 100 using communications component 440. The communicationscomponent 440 may implement any well-known communications techniques andprotocols, such as techniques suitable for use with packet-switchednetworks (e.g., public networks such as the Internet, private networkssuch as an enterprise intranet, and so forth), circuit-switched networks(e.g., the public switched telephone network), or a combination ofpacket-switched networks and circuit-switched networks (with suitablegateways and translators). The communications component 1240 may includevarious types of standard communication elements, such as one or morecommunications interfaces, network interfaces, network interface cards(NIC), radios, wireless transmitters/receivers (transceivers), wiredand/or wireless communication media, physical connectors, and so forth.By way of example, and not limitation, communication media 412 includewired communications media and wireless communications media. Examplesof wired communications media may include a wire, cable, metal leads,printed circuit boards (PCB), backplanes, switch fabrics, semiconductormaterial, twisted-pair wire, co-axial cable, fiber optics, a propagatedsignal, and so forth. Examples of wireless communications media mayinclude acoustic, radio-frequency (RF) spectrum, infrared and otherwireless media.

The device 420 may communicate with a device 410 over a communicationsmedia 412 using communications signals 414 via the communicationscomponent 440. The device 410 may be internal or external to the device420 as desired for a given implementation.

The device 420 may host the host OS 120, the host 120 running themigration application 110, source hypervisor 130, and destinationhypervisor 135, with the source VM 140 and destination VM 145 providedby the respective hypervisors 130, 135. The device 420 may also host thefile system 160 storing the virtual disk blocks 190 for the source VMvirtual disk 170 and destination VM virtual disk 175. The migrationapplication 110 may perform the migration of the guest OS 150 from thesource VM 140 to the destination VM 145 on the device 420.

The device 410 may provide support or control for the migrationoperations of the migration application 110 and/or the hostingoperations of the device 420 and host 120. The device 410 may comprisean external device externally controlling the device 420, such as wheredevice 410 is a server device hosting the guest OS 150 and the device410 is a client administrator device used to administrate device 410 andinitiate the migration using migration application 110. In some of thesecases, the migration application 110 may instead be hosted on the device410 with the remainder of the virtual machine migration system 100hosted on the device 420. Alternatively, the device 410 may have hostedthe migration application 110 as a distribution repository, with themigration application 110 downloaded to the device 420 from the device410.

Distributed Embodiments

FIG. 5 illustrates a block diagram of a distributed system 500. Thedistributed system 500 may distribute portions of the structure and/oroperations for the virtual machine migration system 100 across multiplecomputing entities. Examples of distributed system 500 may includewithout limitation a client-server architecture, a 3-tier architecture,an N-tier architecture, a tightly-coupled or clustered architecture, apeer-to-peer architecture, a master-slave architecture, a shareddatabase architecture, and other types of distributed systems. Theembodiments are not limited in this context.

The distributed system 500 may comprise a client device 510 and serverdevices 550 and 570. In general, the client device 510 and the serverdevices 550 and 570 may be the same or similar to the client device 420as described with reference to FIG. 4. For instance, the client device510 and the server devices 550 and 570 may each comprise a processingcomponent 530 and a communications component 540 which are the same orsimilar to the processing component 430 and the communications component440, respectively. In another example, the devices 510, 550, and 570 maycommunicate over a communications media 512 using communications signals514 via the communications components 540. The distributed system 500may comprise a distributed file system implemented by distributed fileservers 560 including file servers 560-1 through 560-n, where the valueof n may vary in different embodiments and implementations. The localstorage of the client device 510 and server devices 550, 570 may work inconjunction with the file servers 560 in the operation of thedistributed file system, such as by providing a local cache for thedistributed file system primarily hosted on the file servers 560 so asto reduce latency and network bandwidth usage for the client device 510and server devices 550, 570.

The client device 510 may comprise or employ one or more client programsthat operate to perform various methodologies in accordance with thedescribed embodiments. In one embodiment, for example, the client device510 may implement the migration application 110 initiating, managing,and monitoring the migration of the guest OS 150 from the source VM 140to the destination VM 145. The client device 1310 may use signals 1314to interact with the source hypervisor 130, destination hypervisor 135and/or guest OS 150 while they are running on each of the source VM 140and destination VM 145, and file servers 1360.

The server devices 550, 570 may comprise or employ one or more serverprograms that operate to perform various methodologies in accordancewith the described embodiments. In one embodiment, for example, theserver device 550 may implement a source host OS 520 hosting the sourcehypervisor 130 providing the source VM 140. The server device 550 mayuse signals 514 to receive control signals from the migrationapplication 110 on client device 510 and to transmit configuration andstatus information to the migration application 110. The server device550 may use signals 514 communicate with the file servers 560 both forthe providing of source VM 140 and for the migration of guest OS 150from the source VM 140 to the destination VM 145.

The server device 570 may implement a destination host OS 525 hostingthe destination hypervisor 135 providing the destination VM 145. Theserver device 570 may use signals 514 to receive control signals fromthe migration application 110 on client device 510 and to transmitconfiguration and status information to the migration application 110.The server device 570 may use signals 514 communicate with the fileservers 560 both for the providing of destination VM 145 and for themigration of guest OS 150 to the destination VM 145 to the source VM140.

In some embodiments, the same server device may implement both thesource hypervisor 130 and the destination hypervisor 135. In theseembodiments, the migration application 110 hosted on a client device 510may perform the migration of the guest OS 150 from the source VM 140 tothe destination VM 145 on this single server device, in conjunction withmigration operations performed using the distributed file system.

An exemplary method, medium, and system for converting one or more dataobjects managed by a source hypervisor into data objects managed by adestination hypervisor is next described with reference to FIGS. 6A-6C.

Exemplary Methods, Mediums, and Systems

FIG. 6A depicts an exemplary conversion method, which may be implementedas computer-executable instructions stored on a non-transitory computerreadable medium, as illustrated in FIG. 6B. Corresponding exemplarysystem-level interactions are depicted in FIG. 6C.

With reference to FIG. 6A, at step 602 the system receives thedestination VM hypervisor type and the requested destination path. Thedestination VM type and requested destination path may be specified aspart of the above-noted convert command which migrates all of the dataof the source VM to the destination VM. Alternatively or in addition, acommand may specify or may separately indicate one or more data objects,disks, or other data components to be converted from the source VM tothe destination VM.

The requested destination path may be specified in a formatcorresponding to the canonical destination path, and may be specified ina hypervisor-agnostic format. In other words, the requested destinationpath does not need to be specified in the format specific to thehypervisor of the destination VM. For example, the canonical destinationpath may be of the form:

/Volume Junction Path/Path Name

This type of path may be used when the destination path is on a givenstorage device. The destination path may utilize a storage-centric pathfor the canonical path, because the data to be moved will be stored onthe given storage eventually. Inside of a given source or destinationVM, the canonical destination path may uniquely identify a storagelocation in a manner that is independent of the formatting or specificdata storage concepts applied by the VM's hypervisor.

The destination path is the location in which new VM objects (e.g.,vdisks) corresponding to the source VM objects will be placed. When adestination path is specified, the VM objects may not exist yet. Whenthe VM exists, the VM name may be used for the reference.

Step 602 may be carried out by a command interface module 616, asdepicted in FIG. 6B.

Once the destination path has been specified using the canonicaldestination path formatting, the destination path may be translated ormapped to a corresponding hypervisor-specific destination locationspecified in the hypervisor-specific format. This may occurautomatically behind-the-scenes, and away from the visibility of the enduser, thereby reducing the amount of interaction required of the user.In order to determine the destination-side location corresponding to thecanonical destination path, at step 604, the system may retrieve adestination-side storage mapping. The destination-side storage mappingmay be stored in the storage mapping 50 (FIGS. 2 and 6C).

The destination-side storage mapping may represent a translation of thecanonical destination path into a destination location formattedaccording to the destination VM hypervisor's specific or proprietaryformatting requirements. The translation may be in the form of, forexample, one or more rules or algorithms for converting a canonicaldestination path into a hypervisor-specific location format.

Alternatively or in addition, the storage mapping 50 may be in the formof a database or tree structure representing the destination-sidestorage locations assigned to the destination hypervisor. The storagelocations may be stored in pairs including thedestination-VM-hypervisor-specific formatting for the destinationlocation, and the canonical destination path to the destinationlocation. The system may query the storage mapping 50 using thecanonical destination path as a key, and the storage mapping 50 mayreturn the corresponding destination-VM-hypervisor-specific formatting.In order to facilitate representing the storage mapping 50 in thismanner, each time a new storage location is created, or an old storagemapping is destroyed, in the destination VM, the storage mapping may beupdated by adding or removing a corresponding canonical/proprietarypair.

Step 604 may be carried out by a storage mapping module 618, as depictedin FIG. 6B.

At step 606, the system may use the destination-side storage mappingretrieved in step 604 to identify the destination location. This mayinvolve applying the rules or algorithms retrieved at step 604 toconvert the canonical destination path into a hypervisor-specificformat. Alternatively or in addition, the storage mapping 50 may bequeried using the canonical destination path and may return thehypervisor-specific destination location.

In addition to the information specified in the canonical destinationpath, additional information may be required or useful. For example, thecanonical destination path specified at step 602 may be unique insidethe storage virtual machine (SVM); however, in some cases the system mayneed to retrieve general information about the location of the SVM'sdisks in order to apply the canonical destination path. Therefore, usingthe destination VM name specified in step 602, the system may identifythe location of the disks assigned to or managed by the destination VM.

This may be achieved by querying the destination VM for information, asdescribed in more detail in connection with step 706 of FIG. 7.Alternatively or in addition, the storage OS 16 may manage the virtualmachines 20 and may track the storage volumes 22 assigned to each VM 20(FIG. 1). Based on the information tracked by the storage OS 16, and theidentification of the destination VM received in step 602, the storageOS 16 may identify the particular storage device 18, disk, and/orpartitions assigned to the destination VM, as well as the specific node12 or server where the assigned storage locations are located. Thestorage OS 16 may therefore be queried, using the destination VMidentified in step 602, to supplement the information provided in theoriginal convert command and/or the storage mapping 50.

Step 606 may be carried out by a location identification module 620, asdepicted in FIG. 6B.

At step 608, the system may identify one or more hypervisor-agnosticdata objects containing the data to be migrated from the source VM tothe destination VM. The storage OS 16 may store data for the virtualmachines managed by the storage OS in a common, hypervisor-agnostic orhypervisor-independent format. The data may then be exposed according tothe VM's hypervisor-specific storage format. For example, as shown inFIGS. 3 and 6C, some of the source VM's data may be stored as dataobjects 630 that are in a format specified by the storage OS 16, eitherin a virtual disk block 191 specific to the source VM or in virtual diskblocks 190 that are common between multiple different VMs. The dataobject 630 may be exposed as a hypervisor-specific data object 626 atthe source VM, using data path formatting specific to the source VM'shypervisor. Depending on whether the original command in step 602specified that all or only some of the source VMs data objects bemigrated, the system may identify which of the disk blocks 190, 191include the hypervisor-agnostic data objects 630 corresponding to thesource VM-specific data objects 626 to be migrated.

Step 608 may be carried out by an object identification module 622, asdepicted in FIG. 6B.

The disk blocks 190, 191 are mapped to the source VM virtual disk 170,as shown in FIG. 3. In order to migrate the data objects from the sourceVM to the destination VM, the mapping may be updated so that thedestination VM virtual disk 175 points to the locations at which thedata is stored, and may add new metadata and/or configurationinformation to be stored by the destination VM according to thedestination VM's specific data storage requirements or configurations.Therefore, at step 610, the system may issue a command, which may be ahypervisor-agnostic command of the storage operating system 16, to copyone or more source object(s) 626 to the destination location identifiedat step 606. The command may be performed on or with respect to thehypervisor-agnostic data objects 630 identified in step 608. The commandmay cause the destination VM virtual disk 175 to create a new object628, at the destination location identified in step 606, which containsa copy of (or points to) the hypervisor-agnostic data object 630identified in step 608.

Step 610 may be carried out by a conversion module 624, as depicted inFIG. 6B.

With reference to FIG. 6B, an exemplary computing system may store, on anon-transitory computer-readable medium 612, instructions that, whenexecuted, cause the computing system to perform the steps describedabove in connection with FIG. 6A. The instructions may be embodied inthe form of logic 614. The logic 614 may include: a command interfacemodule 616 configured to execute instructions corresponding to step 602of FIG. 6A; a storage mapping module 618 configured to executeinstructions corresponding to step 604 of FIG. 6A; a locationidentification module 620 configured to execute instructionscorresponding to step 606 of FIG. 6A; an object identification module622 configured to execute instructions corresponding to step 608 of FIG.6A; and a conversion module 624 configured to execute instructionscorresponding to step 610 of FIG. 6A.

Data Migration

As noted above, the command specifying that the data object(s) should bemigrated may specify that all of the data of the source VM should bemigrated to the destination VM. This may be, for example, the result ofa “convert” command that migrates the totality of the source VM into adestination VM (including data and other resources, such as VM networkinterfaces, etc). The source VM may effectively be recreated as a new VMmanaged by the destination VM's different type of hypervisor. Ingeneral, the procedure for migrating a VM from one hypervisor to anotherinvolves the following steps, described with reference to FIG. 7.

At step 702, a configuration may be established. The configuration maybe established using configuration cmdlets 34. The configuration mayspecify details of the source and destination hypervisors, VMs, guestOS, and/or storage components involved in the migration, as well asdetails regarding the network configuration of the source VM anddestination VM.

For example, the source VM may be provided by a source hypervisor, andthe destination VM may be provided by a destination hypervisor. Thesource hypervisor and destination hypervisor may differ in hardwarevirtualization so as to prevent a guest OS running on the source VM frommaking full use of the destination VM without reconfiguration. Forexample, the networking configuration of the guest OS may beincompatible with the virtualized networking hardware presented to theguest OS as part of the virtualized hardware environment of thedestination VM.

The configuration information collected in step 702 may include anNIC-to-MAC mapping between one or more network interfaces of the sourceVM and media access control addresses assigned to the one or morenetwork interfaces of the source VM. This mapping may allow a logic flowto recreate the associations between non-virtualized, physical NICs andthe virtualized NICs of the virtualized hardware environment despitechanges in how the virtualized hardware environment is created.

The configuration information may also include the locations of anystorage resources used by the source VM and/or the destination VM.

As part of establishing the configuration, initial configurationparameters may be received by the migration server at step 704. Someinitial configuration parameters may be specified through a script, andmay be provided by a user. The initial configuration parameters mayinclude: hypervisor information (e.g., the IP address and credentialsfor each hypervisor's server, such as an ESX server or a HyperV server);a network mapping (e.g., ESX vSwitch A to HyperV vSwitch B; because ESXand HyperV use different virtual switches in this example, the mappingneeds to be specified to carry out the migration), information for theData ONTAP storage cluster (such as login credentials and the cluster'sIP address), information about the Guest OS; and other configurationparameters.

Using the initial configuration parameters, the migration server maydiscover, at step 706, more detailed virtual machine and Guest OSinformation. For example, based on an input VM name, the migrationserver may query the VM to discover: the VM configuration (e.g., thenumber of CPUs, memory size, information about a DVD drive attached tothe VM, etc.); a list of virtual disks with backend storage locations;NIC cards associated with the VM; and a disk driver mapping, among otherpossibilities. Some or all of these steps may also be performed inconnection with step 606 of FIG. 6A.

The configuration may be established at step 702 via cmdlets called by ascript. The cmdlets may issue commands to the migration server using APIcommands, and the API commands may have a one-to-one correspondence tothe cmdlets.

At step 708, a “convert” command may be called at the client (e.g., adedicated “convert” cmdlet may be called through a script). The convertcommand may specify a name of a VM, as well as a direction of conversion(e.g., by specifying a source VM and a destination VM). The convertcommand may utilize the initial configuration parameters and theconfiguration information that was discovered by the migration serverbased on the initial configuration parameters.

The client's convert command may call, at step 710, a correspondingconvert command in the migration server's interface (e.g., serverinterface 40). The convert command is accepted by the web server 42 andsent to the Hypervisor Shifting API 44. The Hypervisor Shifting API 44in turn calls upon an appropriate service (e.g., first VM service 46 anda second VM service 46, which may be, for example, a Hyper-V Service orthe VMWare Service, although other options are possible), depending onthe direction of the conversion, in order to issue hypervisor-specificAPI commands to effect the migration.

At step 712, the migration server obtains a storage mapping 50 (e.g., alist of disks, storage locations, etc.) for the source and/ordestination VMs. This may correspond, in some embodiments, to step 604,described above. As noted above, the data may be stored in an ONTAP Dataformat, but may be exposed in different manners depending on the type ofVM that stored the data. The storage mapping 50 may map thehypervisor-specific style of exposing the data for each VM to a commondata storage format.

At step 714, the migration server 32 discovers the destination path(i.e., the location of the destination disk directory at which converteddata from the source VM will be stored) based on data obtained from thestorage mapping. This may correspond, in some embodiments, to step 606,described above. The migration server then calls a Disk ConversionLibrary to convert the source VM data into a format compatible with thedestination VM disk type.

At this stage, the migration server 32 has generated destination diskscapable of being read by the destination VM. At step 716, the migrationserver now starts the source VM, and stores information (e.g., thesource IP address, an authenticated user name and password, connectingswitch information, etc.) in the source VM at step 718. The migrationserver then contacts the destination host at which the destination VMwill be set up, and creates a new VM using the generated destinationdisks at step 720. The stored information is copied to the new VM atstep 722 (this may correspond to steps 608 and 610, discussed above),and the conversion process is complete.

Computer-Related Embodiments

The above-described method may be embodied as instructions on a computerreadable medium or as part of a computing architecture. FIG. 8illustrates an embodiment of an exemplary computing architecture 800suitable for implementing various embodiments as previously described.In one embodiment, the computing architecture 800 may comprise or beimplemented as part of an electronic device. Examples of an electronicdevice may include those described with reference to FIG. 8, amongothers. The embodiments are not limited in this context.

As used in this application, the terms “system” and “component” areintended to refer to a computer-related entity, either hardware, acombination of hardware and software, software, or software inexecution, examples of which are provided by the exemplary computingarchitecture 800. For example, a component can be, but is not limited tobeing, a process running on a processor, a processor, a hard disk drive,multiple storage drives (of optical and/or magnetic storage medium), anobject, an executable, a thread of execution, a program, and/or acomputer. By way of illustration, both an application running on aserver and the server can be a component. One or more components canreside within a process and/or thread of execution, and a component canbe localized on one computer and/or distributed between two or morecomputers. Further, components may be communicatively coupled to eachother by various types of communications media to coordinate operations.The coordination may involve the uni-directional or bi-directionalexchange of information. For instance, the components may communicateinformation in the form of signals communicated over the communicationsmedia. The information can be implemented as signals allocated tovarious signal lines. In such allocations, each message is a signal.Further embodiments, however, may alternatively employ data messages.Such data messages may be sent across various connections. Exemplaryconnections include parallel interfaces, serial interfaces, and businterfaces.

The computing architecture 800 includes various common computingelements, such as one or more processors, multi-core processors,co-processors, memory units, chipsets, controllers, peripherals,interfaces, oscillators, timing devices, video cards, audio cards,multimedia input/output (I/O) components, power supplies, and so forth.The embodiments, however, are not limited to implementation by thecomputing architecture 800.

As shown in FIG. 8, the computing architecture 800 comprises aprocessing unit 804, a system memory 806 and a system bus 808. Theprocessing unit 804 can be any of various commercially availableprocessors, including without limitation an AMD® Athlon®, Duron® andOpteron® processors; ARM® application, embedded and secure processors;IBM® and Motorola® DragonBall® and PowerPC® processors; IBM and Sony®Cell processors; Intel® Celeron®, Core (2) Duo®, Itanium®, Pentium®,Xeon®, and XScale® processors; and similar processors. Dualmicroprocessors, multi-core processors, and other multi-processorarchitectures may also be employed as the processing unit 804.

The system bus 808 provides an interface for system componentsincluding, but not limited to, the system memory 806 to the processingunit 804. The system bus 808 can be any of several types of busstructure that may further interconnect to a memory bus (with or withouta memory controller), a peripheral bus, and a local bus using any of avariety of commercially available bus architectures. Interface adaptersmay connect to the system bus 808 via a slot architecture. Example slotarchitectures may include without limitation Accelerated Graphics Port(AGP), Card Bus, (Extended) Industry Standard Architecture ((E)ISA),Micro Channel Architecture (MCA), NuBus, Peripheral ComponentInterconnect (Extended) (PCI(X)), PCI Express, Personal Computer MemoryCard International Association (PCMCIA), and the like.

The computing architecture 800 may comprise or implement variousarticles of manufacture. An article of manufacture may comprise acomputer-readable storage medium to store logic. Examples of acomputer-readable storage medium may include any tangible media capableof storing electronic data, including volatile memory or non-volatilememory, removable or non-removable memory, erasable or non-erasablememory, writeable or re-writeable memory, and so forth. Examples oflogic may include executable computer program instructions implementedusing any suitable type of code, such as source code, compiled code,interpreted code, executable code, static code, dynamic code,object-oriented code, visual code, and the like. Embodiments may also beat least partly implemented as instructions contained in or on anon-transitory computer-readable medium, which may be read and executedby one or more processors to enable performance of the operationsdescribed herein.

The system memory 806 may include various types of computer-readablestorage media in the form of one or more higher speed memory units, suchas read-only memory (ROM), random-access memory (RAM), dynamic RAM(DRAM), Double-Data-Rate DRAM (DDRAM), synchronous DRAM (SDRAM), staticRAM (SRAM), programmable ROM (PROM), erasable programmable ROM (EPROM),electrically erasable programmable ROM (EEPROM), flash memory, polymermemory such as ferroelectric polymer memory, ovonic memory, phase changeor ferroelectric memory, silicon-oxide-nitride-oxide-silicon (SONOS)memory, magnetic or optical cards, an array of devices such as RedundantArray of Independent Disks (RAID) drives, solid state memory devices(e.g., USB memory, solid state drives (SSD) and any other type ofstorage media suitable for storing information. In the illustratedembodiment shown in FIG. 8, the system memory 806 can includenon-volatile memory 810 and/or volatile memory 812. A basic input/outputsystem (BIOS) can be stored in the non-volatile memory 810.

The computer 802 may include various types of computer-readable storagemedia in the form of one or more lower speed memory units, including aninternal (or external) hard disk drive (HDD) 814, a magnetic floppy diskdrive (FDD) 816 to read from or write to a removable magnetic disk 818,and an optical disk drive 820 to read from or write to a removableoptical disk 822 (e.g., a CD-ROM or DVD). The HDD 814, FDD 816 andoptical disk drive 820 can be connected to the system bus 808 by a HDDinterface 824, an FDD interface 826 and an optical drive interface 828,respectively. The HDD interface 824 for external drive implementationscan include at least one or both of Universal Serial Bus (USB) and IEEE694 interface technologies.

The drives and associated computer-readable media provide volatileand/or nonvolatile storage of data, data structures, computer-executableinstructions, and so forth. For example, a number of program modules canbe stored in the drives and memory units 810, 812, including anoperating system 830, one or more application programs 832, otherprogram modules 834, and program data 836. In one embodiment, the one ormore application programs 832, other program modules 834, and programdata 836 can include, for example, the various applications and/orcomponents of the system 30.

A user can enter commands and information into the computer 802 throughone or more wire/wireless input devices, for example, a keyboard 838 anda pointing device, such as a mouse 840. Other input devices may includemicrophones, infra-red (IR) remote controls, radio-frequency (RF) remotecontrols, game pads, stylus pens, card readers, dongles, finger printreaders, gloves, graphics tablets, joysticks, keyboards, retina readers,touch screens (e.g., capacitive, resistive, etc.), trackballs,trackpads, sensors, styluses, and the like. These and other inputdevices are often connected to the processing unit 504 through an inputdevice interface 842 that is coupled to the system bus 808, but can beconnected by other interfaces such as a parallel port, IEEE 694 serialport, a game port, a USB port, an IR interface, and so forth.

A monitor 844 or other type of display device is also connected to thesystem bus 808 via an interface, such as a video adaptor 846. Themonitor 844 may be internal or external to the computer 802. In additionto the monitor 844, a computer typically includes other peripheraloutput devices, such as speakers, printers, and so forth.

The computer 802 may operate in a networked environment using logicalconnections via wire and/or wireless communications to one or moreremote computers, such as a remote computer 848. The remote computer 848can be a workstation, a server computer, a router, a personal computer,portable computer, microprocessor-based entertainment appliance, a peerdevice or other common network node, and typically includes many or allof the elements described relative to the computer 802, although, forpurposes of brevity, only a memory/storage device 850 is illustrated.The logical connections depicted include wire/wireless connectivity to alocal area network (LAN) 852 and/or larger networks, for example, a widearea network (WAN) 854. Such LAN and WAN networking environments arecommonplace in offices and companies, and facilitate enterprise-widecomputer networks, such as intranets, all of which may connect to aglobal communications network, for example, the Internet.

When used in a LAN networking environment, the computer 802 is connectedto the LAN 852 through a wire and/or wireless communication networkinterface or adaptor 856. The adaptor 856 can facilitate wire and/orwireless communications to the LAN 852, which may also include awireless access point disposed thereon for communicating with thewireless functionality of the adaptor 856.

When used in a WAN networking environment, the computer 802 can includea modem 858, or is connected to a communications server on the WAN 854,or has other means for establishing communications over the WAN 854,such as by way of the Internet. The modem 858, which can be internal orexternal and a wire and/or wireless device, connects to the system bus808 via the input device interface 842. In a networked environment,program modules depicted relative to the computer 802, or portionsthereof, can be stored in the remote memory/storage device 850. It willbe appreciated that the network connections shown are exemplary andother means of establishing a communications link between the computerscan be used.

The computer 802 is operable to communicate with wire and wirelessdevices or entities using the IEEE 802 family of standards, such aswireless devices operatively disposed in wireless communication (e.g.,IEEE 802.13 over-the-air modulation techniques). This includes at leastWi-Fi (or Wireless Fidelity), WiMax, and Bluetooth™ wirelesstechnologies, among others. Thus, the communication can be a predefinedstructure as with a conventional network or simply an ad hoccommunication between at least two devices. Wi-Fi networks use radiotechnologies called IEEE 802.13x (a, b, g, n, etc.) to provide secure,reliable, fast wireless connectivity. A Wi-Fi network can be used toconnect computers to each other, to the Internet, and to wire networks(which use IEEE 802.3-related media and functions).

FIG. 9 illustrates a block diagram of an exemplary communicationsarchitecture 900 suitable for implementing various embodiments aspreviously described. The communications architecture 900 includesvarious common communications elements, such as a transmitter, receiver,transceiver, radio, network interface, baseband processor, antenna,amplifiers, filters, power supplies, and so forth. The embodiments,however, are not limited to implementation by the communicationsarchitecture 900.

As shown in FIG. 9, the communications architecture 900 comprisesincludes one or more clients 902 and servers 904. The clients 902 mayimplement the client device 14 shown in FIG. 1. The servers 604 mayimplement the server device 104 shown in FIG. 1A. The clients 902 andthe servers 904 are operatively connected to one or more respectiveclient data stores 908 and server data stores 910 that can be employedto store information local to the respective clients 902 and servers904, such as cookies and/or associated contextual information.

The clients 902 and the servers 904 may communicate information betweeneach other using a communication framework 906. The communicationsframework 906 may implement any well-known communications techniques andprotocols. The communications framework 906 may be implemented as apacket-switched network (e.g., public networks such as the Internet,private networks such as an enterprise intranet, and so forth), acircuit-switched network (e.g., the public switched telephone network),or a combination of a packet-switched network and a circuit-switchednetwork (with suitable gateways and translators).

The communications framework 906 may implement various networkinterfaces arranged to accept, communicate, and connect to acommunications network. A network interface may be regarded as aspecialized form of an input output interface. Network interfaces mayemploy connection protocols including without limitation direct connect,Ethernet (e.g., thick, thin, twisted pair 10/100/1000 Base T, and thelike), token ring, wireless network interfaces, cellular networkinterfaces, IEEE 802.11a-x network interfaces, IEEE 802.16 networkinterfaces, IEEE 802.20 network interfaces, and the like. Further,multiple network interfaces may be used to engage with variouscommunications network types. For example, multiple network interfacesmay be employed to allow for the communication over broadcast,multicast, and unicast networks. Should processing requirements dictatea greater amount speed and capacity, distributed network controllerarchitectures may similarly be employed to pool, load balance, andotherwise increase the communicative bandwidth required by clients 902and the servers 904. A communications network may be any one and thecombination of wired and/or wireless networks including withoutlimitation a direct interconnection, a secured custom connection, aprivate network (e.g., an enterprise intranet), a public network (e.g.,the Internet), a Personal Area Network (PAN), a Local Area Network(LAN), a Metropolitan Area Network (MAN), an Operating Missions as Nodeson the Internet (OMNI), a Wide Area Network (WAN), a wireless network, acellular network, and other communications networks.

General Notes on Terminology

Some embodiments may be described using the expression “one embodiment”or “an embodiment” along with their derivatives. These terms mean that aparticular feature, structure, or characteristic described in connectionwith the embodiment is included in at least one embodiment. Theappearances of the phrase “in one embodiment” in various places in thespecification are not necessarily all referring to the same embodiment.Further, some embodiments may be described using the expression“coupled” and “connected” along with their derivatives. These terms arenot necessarily intended as synonyms for each other. For example, someembodiments may be described using the terms “connected” and/or“coupled” to indicate that two or more elements are in direct physicalor electrical contact with each other. The term “coupled,” however, mayalso mean that two or more elements are not in direct contact with eachother, but yet still co-operate or interact with each other.

With general reference to notations and nomenclature used herein, thedetailed descriptions herein may be presented in terms of programprocedures executed on a computer or network of computers. Theseprocedural descriptions and representations are used by those skilled inthe art to most effectively convey the substance of their work to othersskilled in the art.

A procedure is here, and generally, conceived to be a self-consistentsequence of operations leading to a desired result. These operations arethose requiring physical manipulations of physical quantities. Usually,though not necessarily, these quantities take the form of electrical,magnetic or optical signals capable of being stored, transferred,combined, compared, and otherwise manipulated. It proves convenient attimes, principally for reasons of common usage, to refer to thesesignals as bits, values, elements, symbols, characters, terms, numbers,or the like. It should be noted, however, that all of these and similarterms are to be associated with the appropriate physical quantities andare merely convenient labels applied to those quantities.

Further, the manipulations performed are often referred to in terms,such as adding or comparing, which are commonly associated with mentaloperations performed by a human operator. No such capability of a humanoperator is necessary, or desirable in most cases, in any of theoperations described herein, which form part of one or more embodiments.Rather, the operations are machine operations. Useful machines forperforming operations of various embodiments include general purposedigital computers or similar devices.

Various embodiments also relate to apparatus or systems for performingthese operations. This apparatus may be specially constructed for therequired purpose or it may comprise a general purpose computer asselectively activated or reconfigured by a computer program stored inthe computer. The procedures presented herein are not inherently relatedto a particular computer or other apparatus. Various general purposemachines may be used with programs written in accordance with theteachings herein, or it may prove convenient to construct morespecialized apparatus to perform the required method steps. The requiredstructure for a variety of these machines will appear from thedescription given.

It is emphasized that the Abstract of the Disclosure is provided toallow a reader to quickly ascertain the nature of the technicaldisclosure. It is submitted with the understanding that it will not beused to interpret or limit the scope or meaning of the claims. Inaddition, in the foregoing Detailed Description, it can be seen thatvarious features are grouped together in a single embodiment for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimedembodiments require more features than are expressly recited in eachclaim. Rather, as the following claims reflect, inventive subject matterlies in less than all features of a single disclosed embodiment. Thusthe following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment. In the appended claims, the terms “including” and “in which”are used as the plain-English equivalents of the respective terms“comprising” and “wherein,” respectively. Moreover, the terms “first,”“second,” “third,” and so forth, are used merely as labels, and are notintended to impose numerical requirements on their objects.

What has been described above includes examples of the disclosedarchitecture. It is, of course, not possible to describe everyconceivable combination of components and/or methodologies, but one ofordinary skill in the art may recognize that many further combinationsand permutations are possible. Accordingly, the novel architecture isintended to embrace all such alterations, modifications and variationsthat fall within the spirit and scope of the appended claims.

The invention claimed is:
 1. A method, comprising: generating a snapshotof a volume accessible to a source virtual machine managed by a sourcehypervisor; modifying a header of a first virtual disk of the sourcevirtual machine to be compatible with a destination virtual machine tocreate a modified header; and creating a second virtual disk for thedestination virtual machine to comprise the modified header and apointer to content of the first virtual disk within the snapshot of avolume, wherein a destination file path is modified to be in a formatcompatible with the destination virtual machine and a destinationhypervisor based upon configuration information identified by querying astorage mapping using the destination file path to obtain a translationof the destination file path to a destination hypervisor specificdestination location utilized by the destination hypervisor.
 2. Themethod of claim 1, comprising: maintaining the storage mapping as a datastructure that pairs identifiers utilized by an operating system of astorage system hosting the source hypervisor to identifiers utilized bythe destination hypervisor.
 3. The method of claim 1, comprising:modifying the destination file path based upon the destinationhypervisor specific destination location.
 4. The method of claim 1,comprising: updating the storage mapping in real-time based upondetected changes to storage locations assigned to the destinationvirtual machine.
 5. The method of claim 1, wherein the destination filepath is modified to create a modified destination file path.
 6. Themethod of claim 5, comprising: indicating a location of the firstvirtual disk to the destination virtual machine using the modifieddestination file path.
 7. The method of claim 1, wherein the destinationfile path is a canonical file path format of a storage system hostingthe volume.
 8. The method of claim 1, wherein first virtual diskcomprises first data of the source virtual machine that is migrated to alocation corresponding to the destination file path.
 9. The method ofclaim 8, comprising: converting the first data into ahypervisor-agnostic data object.
 10. A non-transitory machine-readablemedia comprising programming code to: generate a snapshot of a volumeaccessible to a source virtual machine managed by a source hypervisor;modify a header of a first virtual disk of the source virtual machine tobe compatible with a destination virtual machine to create a modifiedheader; and create a second virtual disk for the destination virtualmachine to comprise the modified header and a pointer to content of thefirst virtual disk within the snapshot of a volume, wherein adestination file path is modified to be in a format compatible with thedestination virtual machine and a destination hypervisor based uponconfiguration information identified by querying a storage mapping usingthe destination file path to obtain a translation of the destinationfile path to a destination hypervisor specific destination locationutilized by the destination hypervisor.
 11. The non-transitorymachine-readable media of claim 10, comprising programming code to:implement the translation as a rule for converting a canonical form ofthe destination file path into the destination hypervisor specificdestination location having a hypervisor-specification location formatof the destination hypervisor.
 12. The non-transitory machine-readablemedia of claim 10, comprising programming code to: modify thedestination file path based upon the destination hypervisor specificdestination location.
 13. The non-transitory machine-readable media ofclaim 10, comprising programming code to: update the storage mapping inreal-time based upon detected changes to storage locations assigned tothe destination virtual machine.
 14. The non-transitory machine-readablemedia of claim 10, wherein the destination file path is modified tocreate a modified destination file path.
 15. The non-transitorymachine-readable media of claim 14, comprising programming code to:indicate a location of the first virtual disk to the destination virtualmachine using the modified destination file path.
 16. The non-transitorymachine-readable media of claim 10, wherein the destination file path isa canonical file path format of a storage system hosting the volume. 17.The non-transitory machine-readable media of claim 10, wherein firstvirtual disk comprises first data of the source virtual machine that ismigrated to a location corresponding to the destination file path.
 18. Acomputing device, comprising: a memory comprising machine executablecode for performing a method; and a processor coupled to the memory, theprocessor configured to execute the machine executable code to cause theprocessor to: generate a snapshot of a volume accessible to a sourcevirtual machine managed by a source hypervisor; modify a header of afirst virtual disk of the source virtual machine to be compatible with adestination virtual machine to create a modified header; and create asecond virtual disk for the destination virtual machine to comprise themodified header and a pointer to content of the first virtual diskwithin the snapshot of a volume, wherein a destination file path ismodified to be in a format compatible with the destination virtualmachine and a destination hypervisor based upon configurationinformation identified by querying a storage mapping using thedestination file path to obtain a translation of the destination filepath to a destination hypervisor specific destination location utilizedby the destination hypervisor.
 19. The computing device of claim 18,wherein the machine executable code causes the processor to: utilize thetranslation to format the destination file path to the destinationhypervisor specific destination location according to proprietyformatting requirements of the destination hypervisor.
 20. The computingdevice of claim 18, wherein the machine executable code causes theprocessor to: modify the destination file path based upon thedestination hypervisor specific destination location.